1. Field of the Invention
This invention relates to an electrical connector assembly for facilitating the interconnection of a flat cable containing a plurality of signal conductors surrounded by one or more EMI shields to an electrical connector in which predetermined signal and ground positions are established which are not related to the signal and ground configuration of the flat cable.
2. Description of the Prior Art
Multiconductor flat cables, in which a plurality of conductors are disposed within a common insulating web, offer a number of advantages over discrete wire cables. One paramount advantage is that such multiconductor cables can be easily mass terminated to electrical connectors having terminals positioned on centerline spacings corresponding to the centerline spacing of the conductors in the cable. There are, however, a number of multiconductor flat cable configurations in which other considerations dictate that the conductor spacing in the flat cable must differ from the positions occupied by terminals in a multicontact electrical connector. For example, the conductors in a flat cable can be quite small and positioned on extremely close centerlines. Practical manufacturing problems may prohibit the construction of terminals which can be located on the small centerline spacings occupied by the conductors. Examples of such configurations in which the conductors must be deployed to centerlines greater than that occupied in the cable to permit sufficient termination are depicted in U.S. Pat. No. 4,094,566 and in U.S. Pat. No. 4,181,384 where a connector member which is used to displace individual conductors laterally outward beyond their centerline spacing in the flat cable.
In other configurations, it may be necessary to attach a standard electrical connector, intended for use with discrete wires, to a flat cable in which the conductor centerline spacing differs from that of the standard connector. U.S. Pat. No. 4,147,399 discloses a flat cable connector assembly in which fanned out circuit traces are employed to interconnect the conductors of a flat cable with individual terminals positioned in multiple rows of a standard electrical connector. U.S. Pat. No. 4,437,723 discloses still another configuration which permits conductors in a flat cable to be interconnected to terminals in a multirow electrical connector by using intermediate contact elements which permit a transition from the centerline spacing of the conductors in the cable to the terminals positioned in a predetermined contact pattern.
Termination of multiconductor flat cable is even further complicated when ground or EMI shields are employed in the cable to improve the electrical transmission characteristics of the cable. It has been found that balance pair performance can be obtained in a low profile flat cable by encapsulating associated pairs of round wire conductors in a separate shield or ground surrounding each conductor pair. For cables of this type, it is then not only necessary to terminate the signal conductors of each pair, but some provision must be made for terminating the surrounding ground shields. U.S. Pat. No. 4,508,415 and U.S. Pat. No. 4,640,569 each disclose electrical connectors employed with cables employing associated pairs of conductors, each pair being surrounded by a separate shield. In each of these latter devices, however, the shields are not terminated to terminals in the respective multiposition electrical connector. In each case, the shields are interconnected to a surrounding connector shield.
In some applications where a flat cable is substituted for an existing discrete wire cable, it is still necessary to maintain the same signal positions in a standard electrical connector, despite the fact that the conductor arrangement in the flat cable does not correspond to the signal conductor pattern in the standard connector. U.S. Pat. No. 4,062,616 discloses an electrical connector in which a plurality of conductors in a flexible flat cable are terminated to conductors in a standard two row electrical connector. Although that device does provide a suitable means of terminating a plurality of signal conductors using an insulation displacement technique, no provision is made for termination of ground shields surrounding pairs of conductors at positions within the electrical connector which are unrelated to the signal and ground configuration in the cable. Furthermore, that device does not provide means for establishing a continuous outer EMI shield between the cable and the connector.